As will be known to those skilled in the art, in cases where the natural sphincter muscles of a patient have been excised during surgery, an artificial sphincter is often implanted in order to apply occlusive pressures to a lumen (e.g. a urethra) for holding a patient continent. Such an artificial sphincter often includes an occlusion cuff to surround and articulate the urethra and thereby achieve coaptive continence. The occlusion cuss is sometimes filled with fluid so that a corresponding inflation thereof generates occlusive pressures to be applied to the urethra. In certain cases it is desirable for the physician to controllably deliver an additional supply of fluid to the urethra, whereby to produce the minimal amount of occlusive pressure necessary to achieve coaptive continence according to the tissue requirements of the patient. For an example of the aforementioned artificial sphincter, reference may be made to the copending patent application Ser. No. 752,137, filed on July 5, 1985. However, no relatively inexpensive, easily operable device is known by which to permit a physician to deliver fluid to the occlusion cuff while at the same time ascertaining an accurate approximation of the occlusive pressures being applied to the patient's urethra.